MTP copying oddity


I have copied some mp3 files with standard Copy command (the latest non-beta DO 11) with mtp enabled to my walkman (NWZ-S738F), and the files ended up not recognized by the device. To be precise, they were visible and playable, but any tags were not recognized. Disabling mtp support and copying the files again resolved the problem. Is it some mtp peculiarity or should I do something specific for the mtp support to work correctly in my case?